/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.catalog;

import org.apache.flink.annotation.PublicEvolving;

import java.util.List;

/**
 * An index is a copy of selected columns of data, from a table, that is designed to enable very
 * efficient search. An index normally includes a "key" or direct link to the original row of data
 * from which it was copied, to allow the complete row to be retrieved efficiently.
 */
@PublicEvolving
public interface Index {

    /** Get the name of this index. */
    String getName();

    /** Get the columns of this index. */
    List<String> getColumns();

    /** Print the index in a readable way. */
    String asSummaryString();
}
